1. Field of the Invention
The present invention relates to equipment for housing printed circuit cards and more particularly to an apparatus for controlling the insertion, retention and ejection of card cassettes into and out of a cassette cage of a housing.
2. Description of the Prior Art
Printed circuit cards containing integrated circuits are commonly slideably mounted in respective parallel slots or channels of a card-carrying cage to minimize space requirements. Each card contains a set of connectors which are engageable with an associated set of mating connectors at the rear of the associated channel of the cage. While the engagement of the mating sets of conductors on a card and the cage is relatively easy, the disengagement of the set of conductors on the card from the associated mating connectors in the cage can present a problem, particularly when there is a relatively large number of pins on each male connector. Such a large number of pins on each of the male connectors requires a substantial force to disengage from the associated mating connectors. To help resolve this problem, card ejectors are commonly used to remove a printed circuit card from the cage. However, such ejectors are commonly mounted to the printed circuit card itself. As a result, when force is exerted on an ejector (or pair of ejectors) to remove a printed circuit card, that force produces a stress on the printed circuit card which can crack or otherwise damage the card as it is being removed from the cage.
The background art known to applicant at the time of the filing of this application is as follows:
U.S. Pat. No. 3,767,974, Insertion And Extraction Lever For Printed Circuit Cards, by D. J. Donovan, Jr., et al.